Ring tones require etiquette

I've been in many meetings, presentations and brown bags when someone's cell phone has rung and more often than not, this totally disrupts proceedings. Isn't it common sense to mute your phone's ringer when you are in public, especially at work? Apparently not...

When is it appropriate for a clip of 50 Cent's Candy Shop or Green Day's American Idiot to play on your cellphone? What about an angry man shouting 'Answer the damn phone?'

This sort of summarizes my feelings on this matter to a T. I'm not without blame; my phone has also rung at inappropriate times at work but I make an attempt to put my phone into Silent mode while walking from the parking lot to my office. Tell you what, I'll check again right now, so should you.